SA Agulhas II Winter 2017 Cruise: ice edge drifters

Three Trident Sensors Helix beacons (Unit 1,2,3) were deployed about on ice floes close to latitude 62.8 S and longitude 29.8 E on 4th July 2017 to measure sea ice drift.The region where the instruments were deployed (Antarctic Marginal Ice Zone) consisted of first-year ice on average ~50 cm thick. The instruments were deployed by hand by three people, lowered by crane from the ship to the ice on a basket cradle on floes ~5 m in diameter.The temporal resolution is 4 hours. The survival of the sensors depended on staying fixed to the floe and the battery life.Unit 1 provided GPS location from the 5th July 2017 to 1st December 2017, started at 62.84 S and 30.20 E and finished at 61.55 S and 55.99 E.Unit 2 provided GPS location from the 5th July 2017 to 3rd August 2017, started at 62.83 S and 30.20 E and finished at 62.36 S and 31.57 E.Unit 3 provided GPS location from the 5th July 2017 to 15st August December 2017, started at 62.59 S and 29.98 E and finished at 61.16 S and 35.60 E.In the .xlsx submission sheet 1 refers to Unit 1, sheet 2 to Unit 2, and sheet 3 to Unit 3.First column is the Unit Identifier (1,2,3)Second column is the date in the format day/month/yearThird column is the UTC time in the format hh:mm:ssFourth column is the latitude in degrees and decimals, the negative refers to SouthFifth column is the longitude in degrees and decimals, the positive refers to East

2017年7月4日，三套三叉戟传感器Helix信标（Trident Sensors Helix beacons，单元1、2、3）被部署于南纬62.8°、东经29.8°附近的浮冰之上，用于监测海冰漂移。本次仪器部署区域为南极边缘冰区（Antarctic Marginal Ice Zone），平均覆盖厚度约50厘米的一年冰。本次部署由3名人员手工完成，通过起重机将搭载于吊篮的仪器从科考船吊运至直径约5米的浮冰之上。该数据集的时间分辨率为4小时。传感器的正常运行依赖于与浮冰的牢固绑定以及电池续航能力。单元1的GPS位置数据采集时段为2017年7月5日至2017年12月1日，起始坐标为南纬62.84°、东经30.20°，终止坐标为南纬61.55°、东经55.99°。单元2的GPS位置数据采集时段为2017年7月5日至2017年8月3日，起始坐标为南纬62.83°、东经30.20°，终止坐标为南纬62.36°、东经31.57°。单元3的GPS位置数据采集时段为2017年7月5日至2017年12月15日，起始坐标为南纬62.59°、东经29.98°，终止坐标为南纬61.16°、东经35.60°。在本次提交的.xlsx文件中，工作表1对应单元1，工作表2对应单元2，工作表3对应单元3。第一列为单元标识符，取值为1、2、3。第二列为日期，格式为日/月/年。第三列为协调世界时（UTC）时间，格式为hh:mm:ss。第四列为纬度，以度数加小数形式表示，负值代表南纬。第五列为经度，以度数加小数形式表示，正值代表东经。